# A Bundle of Laughs?

To a first approximation, this will not be funny at all to any of you:

I giggled at it, I will confess. I can never get enough insertions of gerbes into a sentence. There’s just something about the total abstractness of the mathematical object placed in the wrong context… oh never mind. A gerbe? Well, I’ll point you to a Wikipedia entry for this mathematical object, which starts:

In mathematics, a gerbe is a construct in homological algebra and topology. Gerbes were introduced by and Jean Giraud (Giraud 1971) following ideas of Alexandre Grothendieck as a tool for non-commutative cohomology in degree 2. They can be seen as a generalization of principal bundles to the setting of 2-categories. Gerbes provide a convenient, if highly abstract, language for dealing with many types of deformation questions especially in modern algebraic geometry. In addition, special cases of gerbes have been used more recently in differential topology and differential geometry to give alternative descriptions to certain cohomology classes and additional structures attached to them.

…and then, rather unkindly, leave you on your own. Sorry. It is enough to know that it’s a bit obscure (relatively). So popping it into everyone’s favourite bit of profundity from Bladerunner is silliness taken to a funny level. There. I’ve over explained it. Anyway, you see this sort of thing from time to time at places like this (remember last year’s find?) and I thought you’d like a look if you’ve never visited such a place yourself.

Interestingly, someone left this scribble on one of the boards here in the corridor at the Physics Center, and people have been just writing around it during their conversations about other things, opting to preserve it for some reason. Perhaps they’re just waiting to me to notice it and put it in a blog post. Maybe it was put there for precisely that purpose… Hmmm.

-cvj